Merge pull request #47 from makermelissa/marquee

Ported Marquee function from FeatherWing library

adafruit_ht16k33/ht16k33.py

@@ -79,7 +79,6 @@ def blink_rate(self, rate=None):
         self._blink_rate = rate
         self._write_cmd(_HT16K33_BLINK_CMD |
                         _HT16K33_BLINK_DISPLAYON | rate << 1)
-        return None
 
     @property
     def brightness(self):
@@ -93,7 +92,6 @@ def brightness(self, brightness):
         brightness = brightness & 0x0F
         self._brightness = brightness
         self._write_cmd(_HT16K33_CMD_BRIGHTNESS | brightness)
-        return None
 
     @property
     def auto_write(self):

adafruit_ht16k33/segments.py

@@ -25,6 +25,7 @@
 =================
 """
 
+from time import sleep
 from adafruit_ht16k33.ht16k33 import HT16K33
 
 __version__ = "0.0.0-auto.0"
@@ -235,6 +236,35 @@ def set_digit_raw(self, index, bitmask):
         if self._auto_write:
             self.show()
 
+    def marquee(self, text, delay=0.25, loop=True):
+        """
+        Automatically scroll the text at the specified delay between characters
+
+        :param str text: The text to display
+        :param float delay: (optional) The delay in seconds to pause before scrolling
+                            to the next character (default=0.25)
+        :param bool loop: (optional) Whether to endlessly loop the text (default=True)
+
+        """
+        if isinstance(text, str):
+            self.fill(False)
+            if loop:
+                while True:
+                    self._scroll_marquee(text, delay)
+            else:
+                self._scroll_marquee(text, delay)
+
+    def _scroll_marquee(self, text, delay):
+        """Scroll through the text string once using the delay"""
+        char_is_dot = False
+        for character in text:
+            self.print(character)
+            # Add delay if character is not a dot or more than 2 in a row
+            if character != '.' or char_is_dot:
+                sleep(delay)
+            char_is_dot = (character == '.')
+            self.show()
+
 class Seg7x4(Seg14x4):
     """Numeric 7-segment display. It has the same methods as the alphanumeric display, but only
        supports displaying a limited set of characters."""

examples/ht16k33_segments_simpletest.py

@@ -54,3 +54,6 @@
     display.set_digit_raw(1, 0b0011111100101101)
     display.set_digit_raw(2, (0b00111111, 0b00101101))
     display.set_digit_raw(3, [0b00111111, 0b00101101])
+
+#Show a looping marquee
+display.marquee('Deadbeef 192.168.100.102... ', 0.2)